We propose a reliable DNA sequencing technique using graphene-based nanopore
device on the basis of our model calculations. Most of the previous proposals
on graphene nanopore based detection techniques rely on tunnelling currents
that are mediated via energy levels introduced by the nucleotides [1]}, [2]}, [3]}, [4]}, [5]}.
On the other hand the current device relies on comparatively large transverse
conduction current which gets modulated in presence of the DNA bases, and
hence gives much high resolving power. Presence of a nucleotide inside
the nanopore modifies the LDOS at and around their characteristic site-energy
and affects the transmission profiles only in the neighbourhood of this energy.
The resulting transverse current is also quite sensitive to DNA bases, and
hence it renders graphene-nanopore system as a very efficient sequencing
device for biomolecular detection. We also propose an unique way of operation
of the device, by fixing the bias voltage across the device and translocating
a ss-DNA through the nanopore, while recording the distinct current responses
corresponding to the different nucleotides. With the two-sublattice symmetry
breaking of graphene due to insertion DNA nucleotides, large current output
and appreciable amount of accuracy, we have been able to put forward an
unique operating principle for sequential detection of DNA bases that
also gives unmatched accuracy even under environmnetal fluctuations (see Appendix)
compared to previous results [6]}, [1]}, [2]}, [9]}, [10]}, [11]}.
In summary, our proposed technique and model calculations provide a comprehensive
details of the effects of the four nucleotides. Hence we think, following this
work high speed unambiguous sequential detection of the DNA bases can be achieved
at a much lower cost.
